Statfs patfnt offiff



0a. 30, 1934. G. CARVELLI 1,979,025

VENTING SYSTEM Filed July 8, 1932 INVENTOR GUSTAF CHEF/17171 I ATI'ORNEY Patented Oct. 30, 1934 STATES PATENT @Fi ifiifi VENTING SYSTEM tion of New York Application July 8, 1932, Serial No. 621,422

2 Claims.

This invention relates to breathing or venting means for engines and other machines having lubricated mechanisms enclosed in a casing.

In the venting of internal combustion engine 5 crankcases, particularly in high performance aircraft engines, considerable difliculty has been experienced from leakage of oil and oil vapor through the breathing passages that have previously been provided. This difficulty becomes increasingly greater as the power of such engines is increased, due to the increased leakage of gas past the pistons, creating a high pressure within the crankcase, and hence continually creating a blast of gas through the breather. Since the crankcase is filled during operation of the engine with a mist of oil, a considerable amount of this oil is carried out through the breather and results in what is commonly known as a dirty engine.

A form of breather has been incorporated in certain aircraft engines known as a crankshaft breather, wherein the protruding portion of a crankshaft is hollow and by suitable oil screens, etc., the breathing action is allowed to be carried on through the hollow crankshaft. By the location of the crankshaft in the central portion of the case, a minimum of oil mist is encountered at its interior open end, and hence effective breathing without an excess of oil spray may take place. However, in other types of internal combustion engines, this form of breather is not suitable.

Particularly, in V-type geared engines, wherein a crankshaft is completely housed within a crankcase, and wherein a propeller shaft protrudes from the crankcase, the propeller shaft being geared to the crankshaft by spur gears, some other form of breather is necessary. This inven tion has to do with a suitable form of breather for such an engine. As well as locating the breather in the crankcase opposite the closed end of the crankshaft, the crankshaft carries at its forward end a vane centrifuge which picks up the oil mist, which is of greater density than the air or gas within the case, throwing such oil away from the shaft and likewise away from the breather, thus allowing comparatively clean air or gas to pass through the breather from the crankcase.

An object of the present invention is to provide 0 a simple means for positively preventing the escape of oil particles through the breather without restricting the effective venting area.

An additional object is to provide an effective breathing device using a centrifugal member for separating oil from air.

An additional object is to incorporate a centrifugal separator as part of the crankshaft, thus obviating the necessity of adding numerous other moving parts.

An additional object is to incorporate a centrifugal device in the crankshaft of the engine so that the centrifugal device is operated at all times while the engine is running.

In the drawing, Fig. l is a fragmentary longitudinal section through the crankcase of an en- 5 gine, and

Fig. 2 is a perspective view of the rotating element of the breather.

Referring first to Fig. 1, 10 is the end portion of a crankshaft supported in bearings 12 and la in the casing 20. The particular embodiment chosen for illustration represents a geared engine and accordingly the pinion 16 is shown secured to the crankshaft.

A suitable breather 22 is secured in an end cover 24 and this breather has a horizontal extension 26 located partly within the end of the crankshaft 10. The crankshaft is hollow for internal pres sure feed oiling as indicated at 18 and is closed by the hollow cap 28, also shown in enlarged perspective view in Fig. 2. It will be seen that this cap, which rotates with the crank shaft, is provided with a plurality of vanes or ribs 30 surrounding the extended end 26 of the breather, the path of the escaping gases being indicated by the arrows.

The operation of the device is as follows: adequate area for escape of the vented gases is provided in the annular space between breather extension 26 and the cap 28, and the vanes 30 rotate in this annular space. Hence any oil particles which may be carried along by the escaping vapors are set into high speed rotation by the vanes 30 and are immediately thrown outwards by centrifugal force against the inner surface of the cap 28 according to the well known action of centrifugal devices on mixtures having components of varying density. The inner surface of the cap 28 is preferably conical so as to have its larger diameter at the open end, wherefrom the entrapped oil particles will be flung by centrifugal force and thus prevented from entering the breather, without, however, interfering with the freedom of escape of the light vapors.

While the rotating part in which the centrifuging element is secured has been illustrated as the crankshaft of an engine, it will be appreciated that any other shaft may be used for this purpose without departing from the spirit of this invention.

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While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What is claimed is:

1. In an engine, in combination, an oil tight housing, bearings within said housing, a hollow shaft carried for rotation in said bearingsadapted to contain oil for lubricating said bearings, said shaft lying wholly within. said housing, a cap forming a closure for an end of said shaft, and

2. In an engine, in combination, an oil tight housing, bearings within said housing, a hollow shaft carried in said bearings for rotation and adapted to contain oil for lubricating said bearings, said shaft lying wholly within said housing, a cap forming a closure for an end of said shaft and having'a conical recess formed in its outer surface, vanes formed on said cap and extending substantially radially inward from the defining surface of said recess, and a vent tube passing through said casing and terminating within said recess,'whereby said cap acts to centrifuge fluid particles from gas contained within said housing while allowing free ingress or egress of gas to or from said housing, through said vent tube.

GUS'I'AF CARVELLI.

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